It is for example known from the prior art of DE-A-19645678 or DE-A-19811372 to provide for an electrical appliance or domestic appliance an operating panel below which is positioned at a specific location forming a so-called operating field, a pressure-sensitive piezoelectric element. If pressure is applied to the cover, which can be made from thin high-grade steel or aluminum, this pressing action can be evaluated as a desired operation by the piezoelectric element. An associated evaluation or control circuit supplies a signal to the electrical appliance. It is considered disadvantageous in this situation, because the use of piezoelectric elements leads to certain disadvantages, particularly in view of the fact that they are in part mechanically fault-prone and cannot be easily installed into an appliance. It is often frequently necessary to use special manufactures or special components of piezoelectric elements, which have a negative influence on expenditure, particularly manufacturing costs and availability at short notice. The use of other sensor elements such as capacitive or optical sensor elements suffers from the disadvantage that they cannot, or can only with very considerable expenditure, be used behind metallic operating panels or for an optical system optical transparency is vital.